Viral and bacterial counts from filtered water, stained with SYBR Green and counted using epifluorescent microscopy, from samples collected on R/V Knorr cruise KN210-04 in the Western Atlantic Ocean in 2013 (Deep Atlantic DOM project) (NCEI Accession 0277273)

Acquisition Description:
Samples for viral and bacterial counts were collected in 50 mL Falcon tubes, held at 4 degrees C until processing, and processed within two hours. SYBR slides were prepared according to Noble and Fuhruman (Noble and Fuhrman, 1998). Briefly, samples were fixed in v/v 2% formalin and then filtered over a 25 mm 0.02 um anodisc filter (Whatman). Varying volumes were fixed depending on the depth of sample collection (surface and DCM: 3 ml; mesopelagic: 10 ml; AAIW, NADW and AABW: 20 ml). The filter was stained with 2.5x10-3 SYBR Green 1 dilution in nuclease free water, and mounted on a slide with antifade solution (0.1% p-phenylenediamine in 1:1 PBS:Glycerol) and stored at -20 degrees C until enumeration. Under epifluorescence microscopy 10 fields of view were selected at random and >200 viruses and >200 bacteria were counted. Calculations for total number or viruses and bacteria in a sample account for volume filtered, magnification and size of the grid included while counting.

Samples from station 1 and 2 were fixed with the wrong concentration of antifade and therefore faded before accurate counts could be made.

References:
Noble, R. T., and Fuhrman, J. A. (1998). Use of SYBR Green I for rapid epifluorescence counts of marine viruses and bacteria. Aquat Microb Ecol 14 , 113-118. doi: 10.3354/ame014113